Sprite moving as a flag

I have a sprite and I want that it moves as a flag. I need no wind, no shadows, no light, no 3D. Just the movement. Is there a way to do it? I saw on the asset store some assets that do this, but in 3D or with some of the things I said “NO”.
I can do a frame-by-frame animation in animate-aftereffects-name it, but Im looking for a best solution. Is there any?

Here is a cool tutorial I found on how exactly to animate sprites in Unity. Personally I’ve neer done this myself, so I cannot comment on the quality of the tutorial, but it certainly looks pretty indepth.

(I realize we are not supposed to post links here, but this is just too large to copy paste. )